If you don't need anything fancy the stock 5770/5870 works quite well. As long as you're not going to Mojave which requires a Metal-compatible card.

BTW PT10.3.1 runs just fine on OSX 10.9.5; the only thing is the PT uninstaller doesn't work but there are manual steps for that outlined on Avid's site. I ran that on my now-deceased iMac alongside PT11.3.2 until I needed to go to OSX 10.10.5 for some plugins I wanted to run then it was bye-bye PT10.

Thank you musicman691, and everyone else for the help, greatly appreciative.

Thank you musicman691, and everyone else for the help, greatly appreciative.

Something I forgot to mention with respect to video cards in Mac Pros cheesegraters is that even though it's a standard pcie slot not all video cards work right ins aid machines. One of the chief things is no boot screen; that is the old hold down the option key to select the system drive to boot from. If you can live without that then there's not much of a limit to what can work given having the correct drivers.

__________________JackSee profile for system detailsiMac dead & retired as of 11/4/17QAPLA!